Needs download links, sources, and correct syntax for code boxes
In any case you will need to download the ISO image from the current page. Checking the downloaded file. To confirm that the download was successful, you should download the checksum files and then run verification commands such as the following ones: sha256sum -check systemrescue-x.y.z.iso.sha256 sha512sum -check systemrescue-x.y.z.iso.sha512. Install ddrescue on Mac OSX. June 23, 2017 Amber. App name: ddrescue; App description: GNU data recovery tool. With this tiny little command line trick, you can keep your Mac awake for a specified durations or indefinitely. RELATED: How to Temporarily Prevent Your Mac from Sleeping. In the past we’ve told you that you can use a handy little app called Caffeine to keep your Mac awake. Caffeine is great because it has been around awhile, it’s free. (I’d tried it before on Mac OSX but guess what, works on Windows through the WSL too!) A couple things to note: one, if you’re trying to install the Ubuntu version of ddrescue, there’s confusingly a couple different packages named the same thing, and serve the same purpose. An easy way to get ddrescue installed is to install Mac Ports (You can then open a terminal window, type 'sudo port install ddrescue', and the port will install.
A brief manual on how to use ddrescue
Download and burn Ubuntu rescue remix
List the available devices, partitions and file systems
sudo fdisk –l
Change current folder to /mnt. Note that you could mount anywhere but traditionally, mounts are done under this folder.
cd /mnt
Create a subfolder under which the USB drive will be mounted. This USB drive will be used to save the hard disk image. Note that you should use sudo in order to issue the commands as admin.
sudo mkdir folder1
Mount the USB drive on the newly created folder. Use the correct file system (ntfs or vfat for FAT32). Get the correct partition name and number from fdisk -l
mount -t ntfs /dev/sdxn /mnt/folder1
Start ddrescue to make an image of the partition into a file called disk.img (you can select any other file name). logfile is used to log the progress. Again, it can be any file name. This will do a first pass on the partition skipping the failed sectors.
ddrescue /dev/sdxn /mnt/folder1/disk.img logfile
Reissue the same command specifying -r 3 to retry the failed sectors three times. You can select a different number of retries.
ddrescue -r 3 /dev/sdxn /mnt/folder1/disk.img logfile
At this point you can reissue the previous command varying the number of retries to attempt further recovery of sectors that have failed so far.
To access the recovered data, you can either mount the image on a Linux system or copy the disk image into a new hard drive. To mount the image, first create a new mount point (an empty folder under /mnt)
sudo mkdir /mnt/folder2
Mount the image using the loop device that makes the disk image appears as a physical disk
mount -o loop –t ntfs /mnt/folder/disk.img /mnt/folder2
The data can now be accessed by getting into /mnt/folder2 either through the command line or the GUI
To copy the data into a new partition, issue the following command
dd if=/mnt/folder1/disk.img of=/dev/sdxn
where /dev/sdxn refers to the target partition on the new hard drive. Note that this partition should have been created with the exact same size as the original partition. A greater partition than the original would be wasting disk space. Once this is done you can boot Windows and run chkdsk to fix any file system error.
Warning: Issuing dd command with the wrong parameters can destroy your data. Make sure you specify the correct target device after /of=.
EX: # ddrescue -v -r3 /dev/sdc /dev/sdd ddrlog.txt [Source ] [ Destination ] [ logfile for continuity after failure]
Download and burn Ubuntu rescue remix
List the available devices, partitions and file systems
sudo fdisk –l
Change current folder to /mnt. Note that you could mount anywhere but traditionally, mounts are done under this folder.
cd /mnt
Create a subfolder under which the USB drive will be mounted. This USB drive will be used to save the hard disk image. Note that you should use sudo in order to issue the commands as admin.
sudo mkdir folder1
Mount the USB drive on the newly created folder. Use the correct file system (ntfs or vfat for FAT32). Get the correct partition name and number from fdisk -l
mount -t ntfs /dev/sdxn /mnt/folder1
Start ddrescue to make an image of the partition into a file called disk.img (you can select any other file name). logfile is used to log the progress. Again, it can be any file name. This will do a first pass on the partition skipping the failed sectors.
ddrescue /dev/sdxn /mnt/folder1/disk.img logfile
Reissue the same command specifying -r 3 to retry the failed sectors three times. You can select a different number of retries.
ddrescue -r 3 /dev/sdxn /mnt/folder1/disk.img logfile
At this point you can reissue the previous command varying the number of retries to attempt further recovery of sectors that have failed so far.
To access the recovered data, you can either mount the image on a Linux system or copy the disk image into a new hard drive. To mount the image, first create a new mount point (an empty folder under /mnt)
sudo mkdir /mnt/folder2
Mount the image using the loop device that makes the disk image appears as a physical disk
mount -o loop –t ntfs /mnt/folder/disk.img /mnt/folder2
The data can now be accessed by getting into /mnt/folder2 either through the command line or the GUI
To copy the data into a new partition, issue the following command
dd if=/mnt/folder1/disk.img of=/dev/sdxn
where /dev/sdxn refers to the target partition on the new hard drive. Note that this partition should have been created with the exact same size as the original partition. A greater partition than the original would be wasting disk space. Once this is done you can boot Windows and run chkdsk to fix any file system error.
Warning: Issuing dd command with the wrong parameters can destroy your data. Make sure you specify the correct target device after /of=.
EX: # ddrescue -v -r3 /dev/sdc /dev/sdd ddrlog.txt [Source ] [ Destination ] [ logfile for continuity after failure]
OPTIONALLY: If you encounter a crash, you can clone from the back of the drive retrying all of the troubled areas from the back of the disk
# ddrescue -v -R -n /dev/sdc /dev/sdd ddrlog.txt
# ddrescue -v -R -r1 /dev/sdc /dev/sdd ddrlog.txt
This program will not recover the same sector twice (if its already been recovered and logged) because of the way it keeps the log file, so it will not be a waste of time to just repeat the same forward commands over and over if you experience crashes - however it doesnt hurt to just run a reverse command.
# ddrescue -v -R -n /dev/sdc /dev/sdd ddrlog.txt
# ddrescue -v -R -r1 /dev/sdc /dev/sdd ddrlog.txt
This program will not recover the same sector twice (if its already been recovered and logged) because of the way it keeps the log file, so it will not be a waste of time to just repeat the same forward commands over and over if you experience crashes - however it doesnt hurt to just run a reverse command.
Bad sectors are the most common form of hard disk physical damage. They are early signs of a disk crash as it deteriorates over time. A bad sector is a sector on the disk which data cannot be written or read (read errors) due to physical damage or inconsistencies of parity checking bits on disk (CRC or Cyclic Redundancy Check error).To recover your data, the best method is to copy/clone the drive's data to another hard disk before attempting to recover it.
![Ddrescue mac download app Ddrescue mac download app](/uploads/1/3/4/5/134519185/589286303.jpeg)
The new disk must be at least exactly the same size (check the number of LBA sectors) or larger; when larger, it's usually not a problem because the number of heads per cylinder and sectors per head will be the same if both disks use LBA mode. Windows may have some problems in dealing with bad sectors on a damaged hard disk, so the best solution is to use a Linux OS to copy data to another hard disk.
You can also use TestDisk to help analyze the sectors copied from a hard drive with physical problems onto a good drive.
- 2Identifying an HDD's device
- 2.1Identifying an HDD's Linux device
- 3Disk Duplication
Booting from Knoppix, a Linux LiveCD
If you don't have a Linux OS installed, download the Knoppix LiveCD , a free bootable CD with a fully functional Linux OS that runs only in memory!
- Burn the .iso file to CD
- Boot from the CD-ROM
- At the boot prompt, type
knoppix lang=us
for a US keyboard/language. - You are automatically logged in as the user 'knoppix' on a GUI console.
- Launch a Konsole/terminal
(Note: Knoppix has a separate 'Konsole as root' choice, but copy/paste functions are deactivated in it, so we always recommend using the method described below for gaining root privileges from the normal user Konsole.)
Knoppix comes with TestDisk, PhotoRec, dd and dd_rescue. To access hard disks, you need to run these utilities with root (Administrator) privileges.
- To become root from the Knoppix user account, select the Konsole and type
sudo -s
, then press the Enter key. - Now you can use all of the powerful root commands you need for full disk access from this console.
Note for users of Knoppix version 4.0.2 CD:
To use TestDisk under Knoppix 4.0.2, you need to resolve a library problem by first executing:
To use TestDisk under Knoppix 4.0.2, you need to resolve a library problem by first executing:
before running testdisk.
Note for users of Knoppix version 5.1 CD:
To use TestDisk under Knoppix 5.1, you need to resolve a library problem by first executing:
To use TestDisk under Knoppix 5.1, you need to resolve a library problem by first executing:
before running testdisk. This problem shouldn't occur under any other Knoppix versions or with the Linux version avaible from our Download area.
Identifying an HDD's device
Identifying an HDD's Linux device
To list connected hard drives and partitions, the commands fdisk or lshw can be used:
Examples
On Linux kernels after about 2.6.20 all PATA/IDE, SATA, SCSI, and USB drives will show up as /dev/sd? where ? is the assigned drive letter.
Previous kernel versions will show PATA/IDE as /dev/hd? where ? is depends on the location on the PATA bus.
Identifying an HDD's Mac OS X device
To identify the disk/partition numbers,
- Start the Terminal program, found in the
/Applications/Utilities
folder. - type
diskutil list
in the terminal
There are two types of devices:
- raw devices
/dev/rdisk*
, communication is direct with the disk. - buffered devices
/dev/disk*
, data transit via buffer.
When using dd or other duplication programs, always use raw device.
In Mac OS X, partitions are labeled with 'slices'. An example in a volume in GPT format is typically s2, i.e,
rdisk4s2
.![Ddrescue Mac Download Ddrescue Mac Download](/uploads/1/3/4/5/134519185/819962426.png)
Disk Duplication
Once you have verified the device names for your damaged disk and the new one to copy its data to, in a command-shell (CLI) or terminal console (not from within any OS on the damaged hard disk), you can start to duplicate the data.
The classic method using 'dd'
dd is very powerful and can be used to write from disks to files and files to partitions or volumes. However, it is recommended that you try using ddrescue or dd_rescue first, as dd was not conceived to work with damaged and may use suboptimal ways to recover the data, if at all possible, skip to one of the ddrescue section.
- To copy a disk as root, run:
conv=noerror,sync
is used for disks with bad blocks, where the intent is to replace bad blocks with zero placeholders and continue copying.- To copy the disk to an image file:
As a user under Mac OS X or as a Ubuntu user, always prepend the
sudo
command to dd and add your user password to validate the command.Be careful! If you are copying a disk, the destination must also be a disk, not a partition.If you are copying a partition, the destination partition must be large enough. Copying the whole disk is recommended.
Disks should be copied on sector boundaries. T The sector size of most hard drives is currently 512 bytes but the industry is starting to move (post 1999) to a 4KB (4096 byte) sector size. Check your disk specifications to find out.
NB: The UNIX/Linux communities employ the term block to refer to a sector or group of sectors. For example, the Linux fdisk utility normally displays partition table information using 512-byte blocks while also using sector to help describe a disk's size with its phrase, 63 sectors/track. You want the block size for dd to be a power of 2 multiple of the disk sector size.
The default block size for dd is 512 bytes, the operand bs= is used to increase the block size. Bigger block sizes will greatly increase the speed of the copy to a point. That point depends on many factors, but 256K - 500K will be pretty good for most systems. If the block size ends with a ``b, ``k, ``m, or ``g, the number is multiplied by 512, 1024 (1K), 1048576 (1M), or 1073741824 (1G) respectively.
To read/write the disk using a 1MB block size (16 x 512 Byte sectors), the following are equivalent:
bs=1048576
bs=2048b
bs=1024K
bs=1M
Example commands: (use the appropriate device names for your system)
- To copy a disk to a second disk using a 256KB block size, (512 x 512 byte sectors):
- To duplicate an entire disk to another disk using a 16KB block size (32 x 512 byte sectors) and replacing bad block data with zeros:
- To copy a volume/partition from a disk to a partition on another disk using a 256KB block size:
Ddrescue Tutorial
- To copy a disk or partition to a file, If a path is not specified, the file will be created in the current directory:
Kurt Garloff's 'dd_rescue'
If you believe there are many damaged sectors on the drive, you can try using Kurt Garloff's 'dd_rescue' (dd_rescue) instead of dd.
The best method: Antonio Diaz's GNU 'ddrescue'
The best solution - both faster and more efficient - seems to be Antonio Diaz's 'ddrescue'(ddrescue)
Ddrescue Iso
Early detection of bad sectors
Modern hard disks can detect physical problems using SMART Monitoring.
Return to TestDisk
Ddrescue On Windows
Retrieved from 'https://www.cgsecurity.org/mw/index.php?title=Damaged_Hard_Disk&oldid=8238'